All DSLR lenses are marked as to the 35mm film focal length.
A lens marked 24-85mm - f3.5-4.5
when used on a Nikon DSLR:
The Nikon DSLR will see the lens as being 36-127.5mm - f3.5-4.5
You use a multiplier of 1.5
50 mm is usually considered a normal or neutral focal length.
(neither wide angle, nor telephoto).
So the lens that had a pretty good wide angle (24mm) on a 35mm film camera will have less of a wide angle (36mm) on the DSLR camera.
On a Canon DSLR you use a multiplier of 1.6
On a Olympus or Panasonic DSLR you use a multiplier of 2.0
Want to add a Nikon D80 DSLR to my 35mm film SLRs & still use existing F-mount AF lenses. Makers like Canon & Nikon offer same lenses for both their film & DSLR's so they list the true 35mm format focal lengths. What is the focal length conversion for a given 35mm format lense to its digital equivalent and even though the existing lenses have a specific angle of view, is this angle affected when you use the same lense on a DSLR?